JP6700129B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine.

  A crankshaft, an intake camshaft equipped with an intake cam for opening and closing the intake valve, a timing chain for transmitting the rotation of the crankshaft to the intake camshaft, and opening the intake valve by controlling the phase of the intake cam. A control device for an internal combustion engine, comprising: an intake variable valve timing mechanism configured to be able to change a valve timing and a valve closing timing, and controlling the intake variable valve timing mechanism so that a phase of an intake cam becomes a target phase. It is known (for example, refer to Patent Document 1). Although not specified in Patent Document 1, generally, a timing chain includes a plurality of outer links and a plurality of inner links, and a plurality of pins that alternately connect the outer links and the inner links, and the pins are connected to each other. The teeth of the sprocket are adapted to engage with the engagement space formed between the teeth.

JP, 2008-025383, A

  By the way, the interval between the pins of the timing chain, that is, the length of the engagement space is not necessarily constant. That is, when the length of the timing chain portion per a certain number of engaging spaces is referred to as the chain portion length, the chain portion length is relatively long in a certain portion of the timing chain and the remaining portion of the timing chain in the remaining portion of the timing chain. There may be cases where the chain portion length is relatively short. In other words, the timing chain may include a long portion having a relatively long chain portion length and a short portion having a relatively short chain portion length.

  Here, assuming that the region where the timing chain progresses can be divided into a downstream region where the timing chain goes from the intake camshaft to the clan shaft and an upstream region where the timing chain goes from the crankshaft to the intake camshaft, When the portion advances in the downstream region, the long portion suppresses the rotation of the intake cam shaft, so that the phase of the intake cam is retarded with respect to the target phase. Conversely, when the long portion advances in the upstream region, the rotation of the intake camshaft is promoted by the long portion, so that the phase of the intake cam is advanced with respect to the target phase. In any case, there is a problem that the phase of the intake cam deviates from the target phase. When the phase of the intake cam deviates from the target phase, the intake valve opening timing and the valve closing timing deviate from the target timings respectively, and the intake air amount deviates from the target amount, and therefore the engine output becomes the target. May deviate from the value.

  According to the present invention, a crankshaft, a camshaft having a cam for opening and closing an engine valve, a timing chain for transmitting the rotation of the crankshaft to the camshaft, and controlling the phase of the cam. The variable valve timing mechanism configured to change at least one of the valve opening timing and the valve closing timing of the engine valve, and a cyclic correction coefficient in advance so as to vibrate at the same cycle as the rotation cycle of the timing chain. And an electronic control unit configured to control the variable valve timing mechanism by using the periodic correction coefficient so that the phase of the cam becomes a target phase. A device is provided.

  It is possible to more reliably suppress the phase of the cam that drives the opening/closing of the engine valve from deviating from the target phase.

1 is an overall view of an internal combustion engine. It is a schematic diagram showing arrangement of a crank sprocket, an intake sprocket, an exhaust sprocket, etc. It is a schematic diagram explaining an intake variable valve timing mechanism. It is a diagram which shows the valve lift of an intake valve and an exhaust valve. It is a time chart explaining a duty ratio. It is a partial schematic enlarged view of a timing chain. It is a figure which shows the map of target phase CPT. It is a figure which shows the map of base duty ratio DB. It is a schematic diagram explaining a long part, a short part, etc. of a timing chain. FIG. 5 is a diagram showing an example of changes in deviation with respect to changes in crank angle. FIG. 7 is a diagram showing an example of a change in deviation and a change in counter value with respect to a change in crank angle. FIG. 7 is a diagram showing an example of changes in the periodic correction coefficient with respect to changes in the counter value. It is a figure which shows the map of the correction value kPX. It is a flow chart which shows a routine for performing intake cam phase control. It is a flow chart which shows a routine for performing intake cam phase control. It is a diagram which shows another example of the change of a periodic correction coefficient with respect to the change of a counter value.

  Referring to FIG. 1, in an embodiment according to the present invention, 1 is a spark ignition type or compression ignition type internal combustion engine body, 2 is a plurality of cylinders, 3 is an intake valve, 4 is an exhaust valve, 5 is an intake branch pipe, 6 Indicates a surge tank, and 7 indicates an exhaust manifold. The intake valves 3 are opened and closed by corresponding intake cams 8, and the intake cams 8 are provided on a common intake camshaft 9. On the other hand, the exhaust valves 4 are opened and closed by corresponding exhaust cams 10, and the exhaust cams 10 are provided on a common exhaust cam shaft 11.

  Referring to FIG. 2 together with FIG. 1, an intake sprocket 12 is attached to one end of the intake camshaft 9. An exhaust sprocket 13 is attached to one end of the exhaust camshaft 11. Further, a crank sprocket 15 is attached to one end of the crankshaft 14 of the engine body 1. A timing chain 16 is wound around the intake sprocket 12, the exhaust sprocket 13, and the crank sprocket 15. As a result, the rotation of the crankshaft 14 is transmitted to the intake camshaft 9 and the exhaust camshaft 11 by the timing chain 16, and the intake camshaft 9 and the exhaust camshaft 11 are rotated. In FIG. 2, the arrow D16 indicates the traveling direction of the timing chain 16.

  In the embodiment according to the present invention, an intake variable valve timing mechanism 17 is provided which is configured to change the opening timing and closing timing of the intake valve 3 by controlling the phase of the intake cam 8. Referring to FIG. 3, an intake variable valve timing mechanism 17 according to an embodiment of the present invention includes a cylindrical housing 17a that rotates integrally with the intake sprocket 12 and a cylindrical housing 17a that rotates integrally with the intake camshaft 9. A rotating shaft 17b rotatable relative to the housing 17a, a plurality of partition walls 17c extending from an inner peripheral surface of the cylindrical housing 17a to an outer peripheral surface of the rotating shaft 17b, and an outer circumference of the rotating shaft 17b between the partition walls 17c. A vane 17d extending from the surface to the inner peripheral surface of the cylindrical housing 17a, and an advance hydraulic chamber 17e and a retard hydraulic chamber 17f that are alternately formed between the partition wall 17c and the vane 17d. In FIG. 3, an arrow D12 indicates the rotation direction of the intake sprocket 12 by the timing chain 16.

  In the embodiment according to the present invention, the phase of the intake cam 8 or the intake cam shaft 9 is controlled by controlling the supply of hydraulic oil to the hydraulic chambers 17e and 17f and the discharge of hydraulic oil from the hydraulic chambers 17e and 17f. The hydraulic oil supply and discharge control is performed by the hydraulic oil supply control valve 18. The hydraulic oil supply control valve 18 includes a hydraulic oil supply port 18b discharged from a hydraulic pump 18a, a pair of drain ports 18c and 18d, hydraulic ports 18e and 18f respectively connected to hydraulic chambers 17e and 17f, and a port. A spool valve 18g that controls the communication between the 18b, 18c, 18d, 18e, and 18f is provided, and an actuator 18h such as an electric motor that drives the spool valve 18g.

  When the spool valve 18g is moved leftward in FIG. 3 by the actuator 18h to the advanced position, the supply port 18b communicates with the hydraulic port 18e and the hydraulic port 18f communicates with the drain port 18d. As a result, hydraulic oil is supplied to the advance hydraulic chamber 17e, and hydraulic oil is discharged from the retard hydraulic chamber 17f. Therefore, the rotary shaft 17b is rotated relative to the intake sprocket 12 on the advance side A. That is, the phase of the intake cam 8 or the intake cam shaft 9 is advanced. On the other hand, when the spool valve 18g is moved rightward in FIG. 3 to the retard position by the actuator 18h, the supply port 18b is communicated with the hydraulic port 18f and the hydraulic port 18e is communicated with the drain port 18c. As a result, the hydraulic oil is supplied to the retarding hydraulic chamber 17f, and the hydraulic oil is discharged from the advancing hydraulic chamber 17e. Therefore, the rotary shaft 17b is rotated relative to the intake sprocket 12 on the retard side R. That is, the phase of the intake cam 8 or the intake cam shaft 9 is retarded.

  In FIG. 4, the solid line INA shows the intake valve lift amount when the phase of the intake cam 8 is most advanced by the intake variable valve timing mechanism 17, and the solid line INR is the phase of the intake cam 8 is most retarded. Shows the intake valve lift amount when In the embodiment according to the present invention, the phase of the intake cam 8 is controlled between the solid line INA and the solid line INR. For example, when the phase of the intake cam 8 is retarded and the closing timing of the intake valve 3 is retarded, the amount of air returned to the surge tank 6 increases, and therefore the intake air amount decreases. On the other hand, when the phase of the intake cam 8 is advanced and the closing timing of the intake valve 3 is advanced, the amount of air returned to the surge tank 6 decreases and therefore the intake air amount increases.

  Further, in the embodiment according to the present invention, as shown in FIG. 5, the spool valve 18g is held at the advance position for the advance time tDA of the constant cycle time tDPRD and kept at the delay position for the delay time tDR. Hold and these are repeated. In this case, the phase of the intake cam 8 is controlled by controlling the duty ratio D (=tDA/tDPRD) which is the ratio of the advance time tDA to the cycle time tDPRD. When the phase of the intake cam 8 should be advanced, the duty ratio D is increased. That is, the advance time tDA is extended and the delay time tDR is shortened. On the other hand, when the phase of the intake cam 8 should be retarded, the duty ratio D is decreased. That is, the advance time tDA is shortened and the delay time tDR is extended.

  In another embodiment (not shown) of the present invention, the intake variable valve timing mechanism 17 controls the phase of the intake cam 8 to maintain the opening timing of the intake valve 3 while closing the intake valve 3. Is configured to be changeable. In yet another embodiment (not shown), the variable intake valve timing mechanism 17 controls the phase of the intake cam 8 to change the opening timing of the intake valve 3 while maintaining the closing timing of the intake valve 3. It is configured. Therefore, if expressed so as to include these various embodiments, the intake variable valve timing mechanism 17 can change at least one of the valve opening timing and the valve closing timing of the intake valve 3 by controlling the phase of the intake cam 8. It means that it is configured.

  FIG. 6 shows a partially enlarged view of the timing chain 16 of the embodiment according to the present invention. Referring to FIG. 6, the timing chain 16 includes a plurality of outer links 16o and a plurality of inner links 16i, and a plurality of pins 16p that alternately connect the outer links 16o and the inner links 16i. The teeth of the intake sprocket 12 are engaged with the engagement space 16e formed therebetween. In addition, in FIG. 6, LCP represents the interval between the pins 16p adjacent to each other, that is, the length of the engagement space 16e.

  Referring again to FIG. 1, the electronic control unit 30 comprises a digital computer and includes a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a CPU (Microprocessor) 34, which are connected to each other by a bidirectional bus 31. It has an input port 35 and an output port 36. A load sensor 40 that generates an output voltage proportional to the depression amount of the accelerator pedal 39 is connected to the accelerator pedal 39, and the output voltage of the load sensor 40 is input to the input port 35 via the corresponding AD converter 37. Further, a crank angle sensor 41 that generates an output pulse each time the crankshaft 14 rotates, for example, 30 degrees is connected to the input port 35. The CPU 34 calculates the engine speed based on the output pulse from the crank angle sensor 41. An intake cam phase sensor 42 that generates an output pulse each time the intake camshaft 9 rotates, for example, 30 degrees is connected to the input port 35. The CPU 34 calculates the phase of the intake cam 8 based on the output pulse from the intake cam phase sensor 42. On the other hand, the output port 36 is connected to the actuator 18h of the intake variable valve timing mechanism 17 via the corresponding drive circuit 38.

  In the embodiment according to the present invention, the intake variable valve timing mechanism 17 is controlled so that the phase of the intake cam 8 becomes the target phase. For example, the target phase is the phase of the intake cam 8 required to bring the closing timing of the intake valve 3 to the target closing timing, and the target closing timing is the intake air required to bring the intake air amount to the target air amount. It is the closing timing of the valve 3, and the target air amount is the air amount required to bring the engine output to the target output. The target phase CPT is stored in advance in the ROM 32 in the form of the map shown in FIG. 7 as a function of the engine operating state, for example, the depression amount L of the accelerator pedal 39 representing the engine load and the engine speed Ne.

Specifically, the target duty ratio DT corresponding to the target phase CPT is calculated, and the hydraulic oil supply control valve 18 is controlled so that the duty ratio D becomes the target duty ratio DT. The target duty ratio DT is calculated from the following equation (1), for example. In Expression (1), DB represents the base duty ratio, kFB represents the feedback correction coefficient, and kP represents the periodic correction coefficient.
DT=DB+kFB+kP (1)

  The base duty ratio DB is a duty ratio required to bring the phase of the intake cam 8 to the above-mentioned target phase CPT. The base duty ratio DB is stored in advance in the ROM 32 in the form of the map shown in FIG. 8 as a function of the engine operating state, for example, the depression amount L of the accelerator pedal 39 representing the engine load and the engine speed Ne.

  The feedback correction coefficient kFB is for correcting the phase CP of the intake cam 8 so that the actual phase of the intake cam 8 becomes the target phase CPT, and is set to zero when it is not necessary to correct it.

  The periodic correction coefficient kP is for correcting the phase CP of the intake cam 8 so that the actual phase of the intake cam 8 becomes the target phase CPT, and is set to zero when it is not necessary to correct it. Next, the periodic correction coefficient kP will be further described.

  As described at the beginning, the timing chain 16 may include a long portion and a short portion. In the example shown in FIG. 9, the portion surrounded by the chain double-dashed line in the timing chain 16 is the long portion 16L, and the other portions are the short portions 16s.

  On the other hand, the timing chain 16 sequentially advances around the intake sprocket 12, the crank sprocket 15, and the exhaust sprocket 13. It is assumed that the region where the timing chain 16 advances can be divided into a downstream region 18D where the timing chain 16 goes from the intake sprocket 12 to the crank sprocket 15 and an upstream region 18U where the timing chain 16 goes from the crank sprocket 15 to the intake sprocket 12. When the long portion 16L described above advances in the downstream region 18D, the phase of the intake cam 8 is retarded with respect to the target phase CPT. In other words, the deviation DEV (=CP-CPT) of the phase CP of the intake cam 8 detected by the intake cam phase sensor 42 with respect to the target phase CPT has a negative value. Conversely, when the long portion 16L advances in the upstream region 18U, the phase of the intake cam 8 is advanced with respect to the target phase CPT. In other words, the deviation DEV has a positive value. Therefore, since the timing chain 16 sequentially and repeatedly advances in the downstream region 18D and the upstream region 18U, the deviation DEV vibrates. In this case, the deviation DEV vibrates at the crank angle required for the timing chain 16 to make one revolution around the intake sprocket 12, the crank sprocket 15, and the exhaust sprocket 13, that is, the rotation cycle.

  FIG. 10 shows an example of changes in the deviation DEV with respect to changes in the crank angle θ. As shown in FIG. 10, the deviation DEV oscillates between the maximum value DEVmax (>0) and the minimum value DEVmin (<0), that is, the amplitude AMPDEV (=DEVmax-DEVmin), and further, the timing chain 16 It vibrates with the rotation cycle PRD of. In FIG. 10, the crank angle range dθR in which the deviation DEV is a negative value corresponds to the period in which the long portion 16L is proceeding in the downstream region 18D, and the crank angle range dθA in which the deviation DEV is a positive value is long. The portion 16L corresponds to the period in which the portion 16L is traveling in the upstream region 18U. The length of the period dθR, the ratio of the period dθR and the period dθA, the amplitude AMPDEV of the deviation DEV, the maximum value DEVmax, the minimum value DEVmin, etc. are the length of the long portion 16L, the length of the long portion 16L and the length of the short portion 16s. And the length of the downstream region 18D, the ratio of the length of the downstream region 18D to the length of the upstream region 18U, and the like.

  The above-described periodic correction coefficient kP is for making the deviation DEV which oscillates with the rotation period PRD thus zero. For this purpose, the cyclic correction factor kP is preset to oscillate with the rotation period PRD of the timing chain 16. Next, a method of setting the periodic correction coefficient kP according to the embodiment of the present invention will be described.

  FIG. 11 shows an example of changes in the deviation DEV and changes in the counter value CNT with respect to changes in the crank angle θ. The counter value CNT is incremented each time the crank angle θ rotates by a fixed angle, and is returned to zero when the fixed value C1 is reached. The constant value C1 represents the counter value CNT required for the timing chain 16 to make one round. Therefore, the crank angle range from when the counter value CNT reaches the constant value C1 to zero represents the rotation cycle PRD of the timing chain 16. In the embodiment according to the present invention, the maximum value DEVmax and the minimum value DEVmin of the deviation DEV are specified in one rotation cycle PRD. Further, the amplitude AMPDEV (=DEVmax-DEVmin) of the deviation DEV is calculated. Further, the maximum counter value Cmax that is the counter value at which the deviation DEV becomes the maximum value DEVmax and the minimum counter value Cmin that is the counter value at which the deviation DEV becomes the maximum value DEVmax are specified. Further, the interval (=|Cmax−Cmin|) between the maximum counter value Cmax and the minimum counter value Cmin is calculated. In the embodiment according to the present invention, the maximum value DEVmax, the minimum value DEVmin, the amplitude AMPDEV, the maximum counter value Cmax and the minimum counter value Cmin, and the interval dC of the deviation DEV are obtained in a plurality of rotation cycles PRD. , Averaged.

  In addition, in the embodiment according to the present invention, the correction by the periodic correction coefficient kP is performed when the following four correction conditions are satisfied. The first correction condition is that the amplitude AMPDEV of the deviation DEV is larger than the preset amplitude AMPDEV1. The second correction condition is that the distance dC is longer than the preset distance dC1. The third correction condition is that the maximum value DEVmax of the deviation DEV is larger than a predetermined advance side threshold value DEV1A. The fourth correction condition is that the minimum value DEVmin of the deviation DEV is smaller than a predetermined retard side threshold value DEV1R. On the other hand, when any one of these correction conditions is not satisfied, the correction by the periodic correction coefficient kP is not performed. That is, the periodic correction coefficient kP is set to zero. In this way, the phase of the intake cam 8 can be reliably corrected while preventing erroneous correction and overcorrection. In another embodiment (not shown) according to the present invention, the correction by the periodic correction coefficient kP is performed when at least one of the above-described correction conditions is satisfied, and the correction by the periodic correction coefficient kP is otherwise performed. Not done In still another embodiment (not shown) according to the present invention, frequency analysis (FFT) of the deviation DEV is performed, and the first correction condition is satisfied when the rotational primary frequency component is larger than a preset set value. It is determined that

  When the correction is performed by the periodic correction coefficient kP, the periodic correction coefficient kP is set to vibrate in the same cycle as the rotation cycle PRD of the timing chain 16. FIG. 12 shows an example of changes in the cyclic correction coefficient kP with respect to changes in the counter value CNT when the correction is performed using the cyclic correction coefficient kP. In the example shown in FIG. 12, when the counter value CNT reaches the maximum counter value Cmax, that is, when the deviation DEV reaches the maximum value DEVmax, the cyclic correction coefficient kP is set to a positive value (kPX) and held. Next, when the counter value CNT reaches the minimum counter value Cmin, that is, when the deviation DEV reaches the minimum value DEVmin, the cyclic correction coefficient kP is set to a negative value (-kPX) and held. These are sequentially repeated. That is, in the example shown in FIG. 12, the electronic control unit 30 corrects the phase of the intake cam 8 to the retard side with the periodic correction coefficient kP at the time (Cmax) when the deviation DEV becomes the maximum to the advance side. First, at the timing (Cmin) when the deviation DEV becomes maximum on the retard side, the phase of the intake cam 8 is started to be corrected on the advance side with the periodic correction coefficient kP.

  In this case, the cyclic correction coefficient kP is set to increase as the amplitude AMPDEV of the deviation DEV increases, as shown in FIG. The periodic correction coefficient kP is stored in advance in the ROM 32 in the form of the map shown in FIG. 13 as a function of the amplitude AMPDEV of the deviation DEV. In the embodiment according to the present invention, as described above, when the amplitude AMPDEV of the deviation DEV is equal to or less than the set amplitude AMPDEV1, the correction by the periodic correction coefficient kP is not performed. Therefore, in DEV≦AMPDEV1 in FIG. It is zero.

  As described above, in the embodiment according to the present invention, the periodic correction coefficient kP is vibrated according to the vibration of the deviation DEV, and the periodic correction coefficient kP is set according to the amplitude AMPDEV of the deviation DEV. The phase of is deviated more reliably from the target phase.

  In the embodiment of the present invention, the periodic correction coefficient kP is set each time the internal combustion engine is started. That is, the periodic correction coefficient kP is once returned to zero when the internal combustion engine is stopped or started.

  14 and 15 show a routine for executing the intake cam phase control of the embodiment according to the present invention. This routine is executed by interruption at regular intervals. Referring to FIGS. 14 and 15, in step 100, the base duty ratio DB is calculated from the map of FIG. In the following step 101, it is determined whether or not the flag XSET is set. The flag XSET is set when the setting of the periodic correction coefficient kP is completed (XSET=1), and is reset when the internal combustion engine is stopped or started (XSET=0). When the flag XSET is reset, that is, when the setting of the periodic correction coefficient kP is incomplete, the process proceeds from step 101 to step 102.

  Steps 102 to 108 are portions for setting the periodic correction coefficient kP. At step 102, it is judged if the phase of the intake cam 8 or the duty ratio DB is in a steady state. When the phase of the intake cam 8 or the duty ratio DB is in a steady state, the routine proceeds to step 103, where the feedback correction coefficient kFB is modified so that the absolute value of the feedback correction coefficient kFB becomes smaller. That is, the correction action by the feedback correction coefficient kFB is weakened. In this case, the target duty ratio DT is temporarily calculated as the sum of the base duty ratio DB and the weakened feedback correction coefficient kFB, and the hydraulic oil supply control valve is controlled so that the duty ratio D becomes the target duty ratio DT. 18 is controlled. In the following step 104, the deviation DEV is detected, and the maximum value DEVmax, the minimum value DEVmin, and the amplitude AMPDEV of the deviation DEV, the maximum counter value Cmax and the minimum counter value Cmin, and the interval dC are acquired in the plurality of rotation cycles PRD. And averaged. In this case, the deviation DEV is detected with the correction effect of the feedback correction coefficient kFB weakened, so that the deviation DEV can be detected more accurately. In another embodiment (not shown), the deviation DEV is detected when the phase of the intake cam 8 is most advanced or most retarded. In yet another embodiment (not shown), the deviation DEV is detected while temporarily changing and holding the phase of the intake cam 8 to the most advanced or most retarded state. In the following step 105, it is determined whether or not the above-mentioned correction condition is satisfied. When the correction condition is satisfied, the routine proceeds to step 106, where the periodic correction coefficient kP is set. Specifically, the correction value kPX is calculated from the map of FIG. 13, and the cyclic correction coefficient kP has a negative correction value (-kPX) when the counter value CNT is from the maximum counter value Cmax to the minimum counter value Cmin. The counter value CNT is set to a positive correction value (+kPX) from the minimum counter value Cmin to the maximum counter value Cmax. Then, it proceeds to step 108. On the other hand, when the correction condition is not satisfied, or when the phase of the intake cam 8 or the duty ratio DB is in the transient state, the routine proceeds from step 102 to step 107. In step 107, the periodic correction coefficient kP is set to zero. Then, it proceeds to step 108. In step 108, the flag XSET is set (XSET=1). Then, it proceeds to step 109.

  When the flag XSET is set, the routine proceeds from step 101 to step 109. In step 109, the feedback correction coefficient kFB is calculated. In the following step 110, the periodic correction coefficient kP is calculated based on the current counter value CNT. In the following step 111, the target duty ratio DT is calculated using the equation (1). In the following step 112, the hydraulic oil supply control valve 18 is controlled so that the duty ratio D becomes the target duty ratio DT.

  Next, another embodiment of setting the cyclic correction coefficient kP will be described with reference to FIG. In the example shown in FIG. 16, when the counter value CNT becomes a value smaller than the maximum counter value Cmax by a predetermined set value dCA (=Cmax−dCA), that is, when the deviation DEV becomes the maximum value DEVmax. Before, the periodic correction coefficient kP is set to a positive value (kPX) and held. Next, when the counter value CNT becomes a value (=Cmin−dCA) smaller than the minimum counter value Cmin by a predetermined set value dCA, that is, slightly before the time when the deviation DEV becomes the minimum value DEVmin, the periodic correction is performed. The coefficient kP is set to a negative value (-kPX) and held. These are sequentially repeated. That is, in the example shown in FIG. 16, the electronic control unit 30 delays the phase of the intake cam 8 with the periodic correction coefficient kP before the timing (Cmax) when the deviation DEV reaches the maximum on the advance side. The phase of the intake cam 8 is started to be corrected to the advance side by the cyclic correction coefficient kP before the timing (Cmin) when the deviation DEV becomes maximum on the retard side. By doing so, even if there is a response delay of the intake variable valve timing mechanism 17, the phase of the intake cam 8 is more reliably suppressed from deviating from the target phase. In the example shown in FIG. 16, the set value dCA is a constant value. In another embodiment (not shown), the set value dCA is a variable value.

  In the embodiment according to the present invention described so far, the intake variable valve timing mechanism 17 is provided, but the opening timing and the closing timing of the exhaust valve 4 are maintained. In another embodiment (not shown) according to the present invention, an exhaust variable valve timing is constructed in which at least one of the valve opening timing and the valve closing timing of the exhaust valve 4 can be changed by controlling the phase of the exhaust cam 10. However, the opening timing and closing timing of the intake valve 3 are maintained. In yet another embodiment (not shown) according to the present invention, an intake variable valve timing mechanism 17 and an exhaust variable valve timing mechanism are provided. Therefore, when expressed so as to include these examples, at least one of the valve opening timing and the valve closing timing of the engine valve can be changed by controlling the phase of the cam for opening and closing the engine valve. It means that a variable valve timing mechanism is installed. The engine valve includes at least one of the intake valve 3 and the exhaust valve 4.

1 Engine Main Body 3 Intake Valve 8 Intake Cam 9 Intake Camshaft 14 Crankshaft 16 Timing Chain 17 Intake Variable Valve Timing Mechanism 30 Electronic Control Unit

Claims (6)

Crankshaft,
A cam shaft having a cam for opening and closing the engine valve,
A timing chain that transmits the rotation of the crankshaft to the camshaft,
A variable valve timing mechanism configured to change at least one of a valve opening timing and a valve closing timing of the engine valve by controlling the phase of the cam,
A cyclic correction coefficient is set in advance so as to vibrate at the same cycle as the rotation cycle of the timing chain, and the variable valve timing mechanism is configured to use the cyclic correction coefficient so that the phase of the cam becomes a target phase. An electronic control unit configured to control,
A control device for an internal combustion engine, comprising:   The electronic control unit further includes a cam phase sensor that detects the phase of the cam, and the electronic control unit determines the phase of the cam when the amplitude of the deviation of the phase of the cam from the target phase is larger than a preset set amplitude. The control device for an internal combustion engine according to claim 1, wherein the control device is configured to perform correction with the periodic correction coefficient.   The electronic control unit starts correcting the phase of the cam to the retard side with the periodic correction coefficient at the time when the deviation of the phase of the cam from the target phase becomes maximum on the advance side, and the deviation is delayed. The control device for an internal combustion engine according to claim 1 or 2, which is configured to start correcting the phase of the cam toward the advance side with the periodic correction coefficient at a time when the angle becomes maximum.   The electronic control unit begins to correct the phase of the cam to the retard side with the periodic correction coefficient before the time when the deviation of the phase of the cam from the target phase becomes maximum on the advance side, and The internal combustion engine according to claim 1 or 2, wherein the phase of the cam is started to be corrected to the advance side by the periodic correction coefficient before the time when the deviation is maximized to the retard side. Control device.   The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the amplitude of the periodic correction coefficient is set larger as the deviation of the phase of the cam from the target phase increases.   The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the engine valve is an intake valve.

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